| RefNo | HSF/2/1/88 |
| Previous numbers | 32.8.72 |
| Level | Item |
| Title | Copy letter from Major [James Francis] Tennant, Calcutta [Kolkata], to J H [John Herschel] |
| Creator | Tennant; James Francis (1829-1915); British army officer and astronomer |
| Date | 6-9 November 1868 |
| Description | He saw four [spectroscopic] lines [during the solar eclipse], noting that his telescope was not achromotized for such a range. He thinks that the horn [solar prominence] was a vortex, describing two jets of hydrogen bursting from the Sun as seen in photograph number 1, 20,000 miles apart and meeting 16,000 miles above the surface. The vortex they formed was 89,000 miles high at least. He notes another part of the Sun's atmosphere containing heavier vapours, some carried off by the hydrogen jets. He saw sodium and magnesium. There is a calcum line near G but Tennant questions whether it was there, and he discusses other possibilities in his observations. He compares his observations of the prominence to that of Dr [Hermann Wilhelm] Vogel in Aden. Accepting [Gustav] Kirchoff's theory of the spots, with modifications, Tennant considers them to be prominences of slow emission allowing vapour to cool. [Pierre] Janssen spoke of the velocity of movement in the horn to be enormous. [From 9 November] Jannsen has just been with Tennant and has told his story. He will not allow that the corona is part of the Sun, since a passing comet did not affect it. Tennant gives reasons why he disagrees. He decribes how Janssen conceives of the Sun's photosphere. The gas is hydrogen, Janssen believes, and he has discovered how to see the spectra of prominences at any time. Janssen shares some of his observations of prominences. He believes the corona to be terrestrial and does not believe the vapour is projected into the cold atmosphere, but into void space. The spectra are difficult to observe he believes. Tennant describes the supposed plan for looking at the edge of the Sun, and suggests a possible improvement. |
| Extent | 3p. |
| Format | Manuscript |
| PhysicalDescription | Ink on paper |
| AccessStatus | Open |
Fellows associated with this archive
| Code | PersonName | Dates |
| NA6352 | Tennant; James Francis (1829 - 1915); army officer and astronomer | 1829 - 1915 |